The present invention relates to a decontamination method and apparatus, and, in particular, to such a method and apparatus designed to decontaminate certain types of semiconductor wafer handling equipment.
Integrated circuitry is formed on disks of a semiconductor material, typically silicon. These disks are referred to as wafers which must be completely free of contaminants during the formation of microelectronic circuits thereon. However, as is well known, highly corrosive residue oils, films and particulates resulting from the handling and processing of semiconductor wafers contaminate the articles which are used to handle, transport and/or store such wafers. These articles include cassette carriers and boxes, mask holders, wafer boats, boat handles and the like, all of which are generally referred to herein as semiconductor wafer handling equipment. Such handling equipment must be decontaminated after use with each batch of wafers, to prevent contaminants from one wafer batch from contaminating successive batches.
Currently, decontamination of wafer handling equipment of this type is generally accomplished by manually scrubbing the same with liquid detergent, and then drying each separately. In other words, each article is decontaminated separately in separate operations by manual labor. As can be appreciated, with the great number of wafers needed to be processed for the formation of integrated circuitry, this method of decontamination is labor inefficient. Additionally, manual means of decontamination have been found to leave particulates on such equipment of sufficient size to interfere with processing even after manual decontamination.
It is important for reliable production of integrated circuitry on semiconductor wafers, that the wafers be free of static electricity. If the wafer handling equipment carries static electricity, it can be transferred to the wafers and deleteriously affect such circuitry production. Thus, it is important that any static electricity on the wafer handling equipment be removed between use of the same with successive batches of wafers. While others, such as Bok et al., U.S. Pat. No. 921,796, Dexter et al., U.S. Pat. No. 4,208,760, and Cook U.S. Pat. No. 3,393,514, have disclosed various types of cleaning methods and apparatuses for semiconductor wafers themselves, to applicants' knowledge no one has taught how to clean the equipment used for processing such wafers. And while others e.g., Detjen, U.S. Pat. No. Re. 23,788 and German Pat. No. 2,222,688, have disclosed arrangements for cleaning food handling trays and the like, no one has taught a method or an apparatus capable of decontaminating wafer handling equipment and removing static electricity therefrom.